Insurance

BMC Insurance is provided by Howden Group who have run webinars on Club Liability for Affiliated Clubs in 2024 and 2026.

Liability if non-members participate

All members of the club have to be members of the BMC to qualify for the insurance. Ergo anyone who isn't a club member isn't covered. Not surprising!
Public liability covers claims bought by a club member or a member of the public. Unclear whether non-members attending a club meet would be classified as "a member of the public". If so then I see no problem.
In the video repeatedly use the phrase "making claims against the club" which suggests there is a degree or protection for the club as an entity as well as individual members via the policies.
Non-climbing, non-active, i.e. social meets that are club activities are covered. This then leads to the same question of what has raised this issue, what if a non-club member "attends". Thus on the pub crawl you meet someone who is a friend who isn't a club member and they sit with the group is the club then liable? Personally I think this is pushing the realms of credibility.
Important - payment isn't automatic it has to be proven that there was liability. They would have to prove that the club breached their responsibility. Which leads to...
Important - it seems there is very little precedence in either civil or criminal law on which to base any of this. As noted in the video climbers are generally self-reliant and it is actually rare for accidents to occur and rarer that insurance claims are made (the exception being when life-changing injuries are incurred).

Pre-existing conditions - generally not a problem if they are taking part in "recognised activities", but it sounds as though there was no clear answer as it hasn't played out in courts to set a precedence.